A variety of child proof safety closures have been designed and marketed which are intended to prevent young children from opening containers of medicine and other potentially dangerous products. Most of these safety closures prevent accidental opening by children in accordance with their design features, but have a common problem of being difficult for adults to open, particularly the elderly and people who are physically handicapped.
For example, many child proof container systems for aspirin and other medicines utilize arrows or other marks on the closure and container which must be aligned before the closure can be pryed off. These systems appear to work well to prevent accidental opening by children but are not considered to be adult easy, since the alignment marks are hard to see and/or feel, the closure is very tight on the container and difficult to rotate to the exact alignment point, and is also hard to pry off even after proper alignment. The push down and twist safety closure systems now on the market, are apparently good to prevent opening by children hut because of the relatively high push and twist forces needed for opening, are not considered adult easy and are a real problem for the elderly and the handicapped. The above and other child proof closure systems which by design require relatively high forces in one direction or another are difficult for adults to open.
Many safety closures utilizing flexible skirts, thumb tabs and lugs, and tricky locking systems are not successfully marketed due to their design complexity and resulting high cost to manufacture.